Sources tell NBC News that Sandusky's son was in the courthouse Wednesday ready to rebut his father's testimony if Jerry Sandusky had testified

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Former Penn State assistant football coach Jerry Sandusky arrives at his child-sex-abuse trial at the Centre County Courthouse for closing arguments.

The threat of the adopted son of Jerry Sandusky possibly delivering potentially damaging testimony may have prevented his father from taking the stand in his own defense against charges of child-sex abuse, sources tell NBC News.

In a report on the Today Show Thursday morning, Michael Isikoff reported that Matt Sandusky, one of six of Jerry and Dottie Sandusky’s adopted children, was caught by an NBC camera entering the Centre County courthouse Wednesday as rumors swirled that Jerry Sandusky was going to take the stand to explain the so-called love letters and the Bob Costas' interview on Rock Center With Brian Williams.

With Matt Sandusky, 33, in the courthouse, Jerry Sandusky, lawyers and Judge John Cleland went into judge’s chambers. They emerged about 30 minutes later with Jerry Sandusky appearing more somber. At that time Sandusky’s lawyer put to rest any rumors of his client testifying by saying, “the defense rests.”

It’s still not clear what Matt Sandusky -- who Sandusky met through his charity The Second Mile in 1995 and would later adopt when he was 18 -- could have said on the stand and NBC News’ attempts to reach him were unsuccessful. He was a stalwart of his father through much of the trial and even sat with his mother and other family members in court last week.

But, according to NBC News sources, Matt Sandusky contacted prosecutors after the trial began and told them he would provide testimony about some of the events he allegedly witnessed his 68-year-old father commit.

A source close to Sandusky told NBC News that no single factor led to the ex-Penn State assistant coach choosing to not testify.

Closing arguments began Thursday morning and the jury could get the case before the day ends. They will have three less charges to consider after Cleland tossed two counts of involuntary deviate sexual intercourse related to the alleged sexual abuse of an accuser known as Victim 4. Cleland says the charges did not bear out what testimony revealed.

The judge also removed a count that he says was redundant.

Cleland also ruled against a defense motion to dismiss five counts related to a boy who was allegedly seen with Sandusky by a janitor.